NSCollectionView draws nothing - objective-c

Question

I'm trying to set up an NSCollectionView (I have done this successfully in the past, but for some reason it fails this time).
I have a model class called "TestModel", and it has an NSString property that just returns a string (just for testing purposes right now). I then have an NSMutableArray property declaration in my main app delegate class, and to this array I add instances of the TestModel object.
I then have an Array Controller that has its Content Array bound the app delegate's NSMutableArray. I can confirm that everything up to here is working fine; NSLogging:
[[[arrayController arrangedObjects] objectAtIndex:0] teststring]
worked fine.
I then have all the appropriate bindings for the collection view set up, (itemPrototype and content), and for the Collection View Item (view). I then have a text field in the collection item view that is bound to Collection View Item.representedObject.teststring. However NOTHING displays in the collection view when I start the app, just a blank white screen. What am I missing?
UPDATE: Here is the code I use (requested by wil shipley):
// App delegate class
#interface AppController : NSObject {
NSMutableArray *objectArray;
}
#property (readwrite, retain) NSMutableArray *objectArray;
#end
#implementation AppController
#synthesize objectArray;
- (id)init
{
if (self = [super init]) {
objectArray = [[NSMutableArray alloc] init];
}
return self;
}
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
TestModel *test = [[[TestModel alloc] initWithString:#"somerandomstring"] autorelease];
if (test) [objectArray addObject:test];
}
#end
// The model class (TestModel)
#interface TestModel : NSObject {
NSString *teststring;
}
#property (readwrite, retain) NSString *teststring;
- (id)initWithString:(NSString*)customString;
#end
#implementation TestModel
#synthesize teststring;
- (id)initWithString:(NSString*)customString
{
[self setTeststring:customString];
}
- (void)dealloc
{
[teststring release];
}
#end
And then like I said the content array of the Array Controller is bound to this "objectArray", and the Content of the NSCollectionView is bound to Array Controller.arrangedObjects. I can verify that the Array Controller has the objects in it by NSLogging [arrayController arrangedObjects], and it returns the correct object. Its just that nothing displays in the NSCollectionView.
UPDATE 2: If I log [collectionView content] I get nothing:
2009-10-21 08:02:42.385 CollViewTest[743:a0f] (
)
The problem is probably there.
UPDATE 3: As requested here is the Xcode project:
http://www.mediafire.com/?mjgdzgjjfzw
Its a menubar app, so it has no window. When you build and run the app you'll see a menubar item that says "test", this opens the view that contains the NSCollectionView.
Thanks

Answer 1

The problem is that your not correctly using KVC. There is two things you can do.
Method 1: Simple but not so elegant
Use the following code to add the object to the array
[[self mutableArrayValueForKey:#"objectArray"] addObject:test];
This isn't so elegant as you have to specify the variable using a string value, so you will not get compiler warnings when spelt incorrectly.
Method 2: Generate the KVO methods needed for the array "objectArray".
Select the property in your interface declaration
Select Scripts (the script icon in the menubar) > Code > Place
accessor decls on Clipboard
Paste the declarations in the
appropriate spot in your interface file
Select Scripts > Code > Place
accessor defs on Clipboard
Paste the definitions in the
appropriate spot in your implementation file
You can then use a method that looks like
[self insertObject:test inObjectArrayAtIndex:0];